Constructible from `h` and `v`. The lifetime of `h` and `v` are guaranteed to end no earlier than after the `W` is destroyed. The writer shall not access the contents of `h` or `v` before the first call to `init`, permitting lazy construction of the message. The constructor may optionally require that `h` and `v` are `const` references, with these consequences: * If `W` requires that `h` and `v` are const references, then the corresponding serializer constructors for messages with this body type will will accept a const reference to a message, otherwise: * If `W` requires that `h` and `v` are non-const references, then the corresponding serializer constructors for messages with this body type will require a non-const reference to a message.
Constructible from `h` and `v`. The lifetime of `h` and `v` are guaranteed to end no earlier than after the `W` is destroyed. The writer shall not access the contents of `h` or `v` before the first call to `init`, permitting lazy construction of the message. The constructor may optionally require that `h` and `v` are `const` references, with these consequences: * If `W` requires that `h` and `v` are const references, then the corresponding serializer constructors for messages with this body type will will accept a const reference to a message, otherwise: * If `W` requires that `h` and `v` are non-const references, then the corresponding serializer constructors for messages with this body type will require a non-const reference to a message.
The constructor may optionally require that `h` and `v` are `const` references, with these consequences:
* If `W` requires that `h` and `v` are const references, then the corresponding serializer constructors for messages with this body type will will accept a const reference to a message, otherwise:
* If `W` requires that `h` and `v` are non-const references, then the corresponding serializer constructors for messages with this body type will require a non-const reference to a message.
The constructor may optionally require that `h` and `v` are `const` references, with these consequences:
* If `W` requires that `h` and `v` are const references, then the corresponding serializer constructors for messages with this body type will will accept a const reference to a message, otherwise:
* If `W` requires that `h` and `v` are non-const references, then the corresponding serializer constructors for messages with this body type will require a non-const reference to a message.